Structure and Functions in Living Organisms - Gas Exchange

Question 1

what does the thorax contain?

Answer 1

ribs, intercostal muscles, diaphragm, trachea, bronchi, bronchioles, alveoli, pleural membrane

Question 2

what are the ribs?

Answer 2

bone structure that protects internal organs including the lungs

Question 3

what are the intercostal muscles?

Answer 3

muslces between the ribs that move the ribcage during inhalation and exhalation

Question 4

what is the diaphragm?

Answer 4

a sheet of muscles at the bottom of the thorax that changes the volume during inhalation and exhalation

Question 5

what is the trachea?

Answer 5

the windpipe that connects the mouth and nose to the lungs

Question 6

what are the bronchi?

Answer 6

2 thick tubes at the end of the trachea, one for each lung

Question 7

what are bronchioles?

Answer 7

thinner tubes at the end of the bronchi, connected to alveoli

Question 8

what are the alveoli?

Answer 8

tiny air sacs where gas exchange occurs

Question 9

what is the pleural membrane?

Answer 9

thin, moist membrane lining the outside of the lungs for lubrication to reduce friction

Question 10

what happens during inhalation?

Answer 10

• intercostal muslces and diaphragm contract
• thorax volume increases
• pressure decreases and air is drawn in

Question 11

what happens during exhalation?

Answer 11

• intercostal muslces and diaphragm relax
• thorax volume decreases
• pressure increases and air is forced out

Question 12

how are alveoli adapted for gas exchange?

Answer 12

• folded to increase surface area to volume ration
• thin cells walls to decrease diffusion distance
• dense capillary network to provide a rich blood supply to create a strong concentration gradient

Question 13

what is the effect of smoking on air passages?

Answer 13

• tar in cigarettes destroy the cilia, therefore causing the buildup of mucus and increasing risk of bronchitis
• tar in cigarettes contain carcinogens that increases risk of lung cancer

Question 14

what is the effect of smoking on alveoli?

Answer 14

• tar in cigarettes break down alveoli walls and causes them to merge together, decreasing the surface area to volume ratio for gas exchange
• insufficient gas exchange will increase the risk of emphysema

Question 15

what is the effect of smoking on the circulatory system?

Answer 15

• nicotine in cigarettes causes blood vessels to narrow, increasing blood pressure and causing the build-up of fatglobules, increasing risk of coronary heart disease (CHD)
• carbon monoxide from cigarette smoking will bind irreversibly to haemoglobin, reducing capacity of oxygen transport by red blood cells

Question 16

how would you investigate the release of carbon dioxide?

Answer 16

• measure a fixed volume of limewater into a boiling tube
• use a straw and blow into the boling tube

Question 17

how would you investigate the effect of exercise on breathing?

Answer 17

• stationary breathing rate is recorded
• specific exercise will be performed by participants at the same intensity for a fixed period of time
• breathing rate after exercise is recorded